An array substrate of the liquid crystal display (LCD) has a display area and a fan-out area. There are signal lines integrated on the display area for driving the source and the gate on the display area. The fan-out area defines traces, a start end of the trace is soldered with the signal line, and an output end of the trace is electrically connected with conductive lines of the printed circuit board via anisotropic conductive film (ACF). The flexible printed circuit board is electrically connected to the system circuit board, so that an electrical connection is achieved between the display area and the system circuit. It is noted that, through the vertical conductive principle of the electrically conductive particles of the ACF, the output end of trace and the conductive lines of the flexible printed circuit board constitute the electrical connection.
The design of the output ends of the generally fan-out areas is limited by the particle size of the ACF electrically conductive particles, the distance between the conductive lines of the flexible circuit board, and the ability of pressing device. At present, large-size LCD array substrate is designed as a single row layout, and small and medium size LCD array substrate is designed as two rows layout, due to its high integrated circuit density. However, at higher resolution specifications and narrow bezel design requirements, the signal lines and trace structures on the array substrate, the layout of the flexible circuit board, the ACF application material, or the pressing device all need to be updated to cope with the challenges of high density integrated circuits.